[truckster]

Before you start the truck (engine cold) take a look at the carburetor. Move the accelerator linkage all the way back and the choke plate should snap shut. The choke plate is the plate on top of the carburetor at the front. It looks like it's open on all of your pictures. If it is, that would be why you're having a hard time starting the truck. Rather than pouring raw gas in it, give it a shot of starting fluid or even carburetor cleaner and then try to start it immediately (the aerosols evaporate more quickly than gas, so less chance of washing oil off cylinder walls with repeated attempts). I'll bet it fires right up; that indicates your choke is not closing and it needs to be adjusted.

The non-standard distributor you have is a factory GM HEI unit. It's a really good upgrade. Just make sure the timing is set correctly (I like 10-12 degrees initial timing).